CT X-ray collimator including a reinforced collimator blade assembly

Abstract

A collimator blade assembly for a computed tomographic X-ray scanner comprising a blade of X-ray beam stopping material having an aperture for passing X-rays and an X-ray penetrable member closing at least a portion of that aperture to reinforce the material and thereby minimize collimator blade/detector clearances while preventing undesirable collimator blade vibration.

What is claimed is: 
     
       1. A collimator for a computed tomographic X-ray scanner including: (a) a plurality of generally rectangular blades of X-ray beam stopping material each having a longitudinal slot for passing X-rays from a source to a target, said plurality of blades being mounted in star-shaped configuration lengthwise along a rotatable axle;   (b) motor means for rotating said star-shaped configuration of blades; and   (c) means for minimizing vibration of said blades while maximizing the proximity of said slots to one lengthwise edge of each of said blades, said means comprising an X-ray penetrable reinforcing member affixed to each said blade to extend transversely across at least a portion of each of said slots.   
     
     
       2. A collimator for a computed tomographic X-ray scanner including: (a) a plurality of blades of X-ray beam stopping material each having a longitudinal slot for passing X-rays from a source to a target, said plurality of blades being mounted in star-shaped configuration lengthwise along a rotatable axle;   (b) motor means for rotating said star-shaped configuration of blades; and   (c) an X-ray penetrable reinforcing member affixed to each said blade to extend transversely across a portion of its slot and thereby rigidify each of said blades.   
     
     
       3. A collimator for a computed tomographic X-ray scanner comprising a plurality of blades of X-ray beam stopping material, each blade having an aperture for passing X-rays and an X-ray penetrable member closing at least a portion of said aperture to reinforce said blade, said plurality of blades being mounted in star-shaped configuration lengthwise along a rotatable axle, and motor means for rotating said star-shaped configuration of blades. 
     
     
       4. A collimator of claim 3 wherein said aperture is fixed in size and shape. 
     
     
       5. A collimator of claim 1, 2 or 3 wherein said X-ray penetrable members are each affixed to an exterior surface of a corresponding blade. 
     
     
       6. A collimator of claim 1, 2 or 3 including two of said X-ray penetrable members for each blade, one affixed to one exterior surface of each corresponding blade and the other affixed to an opposing exterior surface. 
     
     
       7. A collimator of claim 6 wherein said exterior surfaces are substantially flat and said X-ray penetrable members each comprise a flat plate of X-ray penetrable material. 
     
     
       8. A collimator of claim 1, 2 or 3 wherein said X-ray penetrable members each comprises X-ray penetrable material selected from the group consisting of: plastic, beryllium, graphite reinforced epoxy, and aluminum. 
     
     
       9. A collimator of claim 1, 2 or 3 wherein said X-ray penetrable member absorbs X-rays in a selected energy region of the X-ray spectrum. 
     
     
       10. A collimator of claim 9 wherein said member comprises X-ray penetrable material selected from the group consisting of copper, stainless steel, and titanium. 
     
     
       11. A collimator of claim 2 wherein each said blade has two lengthwise edges and said slot of each blade is located closer to one of said lengthwise edges of said blades than the other. 
     
     
       12. A collimator of claim 3 wherein each said blade has two lengthwise edges and said aperture is located closer to one of said lengthwise edges of said blade than the other.